1. Field of the Invention
The present invention relates to information recording articles requiring various kinds of forgery prevention such as Shinkansen reserved tickets issued by travel agencies and ticket centers, tickets having the value printed on specific forms such as concert tickets, and securities such as bank tickets, bills, stocks, and gift certificates, soft magnetic alloy fibers to be embedded in bases of such articles for forgery prevention, a manufacturing method for soft magnetic alloy fibers, and information recording articles using soft magnetic alloy fibers.
2. Description of the Related Art
Forgery preventive measures for notes as money, securities, and cards having the value equal to cash are taken.
As such a measure, for example, there is a method available for printing security information on a paper sheet with magnetized ink and magnetically detecting the security information. Further, there is another method available for putting a metallic piece with a plate thickness of 20 μm and a width of 0.5 to 1.0 mm into the paper base beforehand and detecting the metallic piece. Furthermore, there is still another method available for mixing metallic fibers such as stainless steel pretreated by a water soluble binder in the paper base and detecting metallic fibers by the electromagnetic property, magnetic property, electromagnetic wave absorptivity, and heat conductivity. There is a further method available for mixing carbon fibers coated with a ferromagnetic metal such as nickel in the paper base and detecting carbon fibers by the electrical measurement such as electromagnetic property measurement, the electromagnetic wave measurement such as microwave inspection, or the magnetic measurement. Furthermore, there is a still further method available for mixing together magnetic polymeric elements composed of a macromolecular material containing magnetic metallic powder irregularly in an information recording medium and magnetically reading magnetic polymeric elements by an MR element (magneto resistance element). Further, there is yet a further method available for reading fibers composed of a magnetic material by a magnetic head in an information recording medium that fibers composed of a magnetic material are mixed together in a base composed of a nonmagnetic material in an optional dispersion state and a plurality of aforementioned bases are laminated integratedly.
In the aforementioned forgery preventive measures, magnetic output detection capable of high-speed reading comparatively easily is generally used for validity determination.
Among the forgery preventive measures, for example, when a metallic piece with a width of 0.5 to 1 mm is to be put into the paper base, the material to be inserted is too thick and a problem is imposed in use. In this case, when a metallic piece of the aforementioned dimension and a metal wire of about 100 to 200 μm in diameter are embedded in a paper, the flexibility of paper sheet in the embedded portion is lost and the shade is often ascertained when looked through, so that there is the possibility of easy forging.
Further, for example, when magnetic polymeric elements with magnetic powder dispersed are to be detected by the MR element, compared with a bulky material of high magnetic permeability, a polymer material such as a polymer which contains magnetic powder and is formed in an extremely fine wire shape is greatly reduced in magnetic permeability. Therefore, in order to read those embedded elements by an MR head, the SN ratio is too small. Further, since a weak signal is handled the reader often requires installation of a magnetic shield and there are many factors for an increase in cost.
Furthermore, when a plurality of bases with fibers composed of a magnetic material coexisting are laminated, the information amount is increased. However, there is a difference in output caused between samples inside the laminate and samples in the neighborhood of the surface and the forgery preventive effect is lower though an increase in cost is required.
As represented by cards or bills, information-recording articles are mostly in a thin paper sheet form. Therefore, magnetic elements coated on or embedded in their surfaces are preferably to be in an extremely fine wire shape or a thin magnetic coating layer. When magnetic reading is to be executed, a material of high magnetic permeability is desirable from the viewpoint of material. As such a material, for example, permalloy, ferrite magnetic powder, and amorphous wire may be cited. However, permalloy must be rolled into a thin plate and it is not practical from the viewpoint of cost. Ferrite magnetic powder is applicable only to magnetic ink and it is technically difficult to produce a long wire. An amorphous wire has a diameter of about 100 to 200 μm under restrictions of the manufacturing conditions. However, when it is drawn into a diameter of several tens μm so as to insert into paper sheets, the magnetic property is deteriorated greatly. Therefore, it is not practical for validity determination.
Furthermore, when a metallic piece or a thread is embedded for the purpose of forgery prevention, if it is large in form, it may be taken out easily and it cannot be said from the viewpoint of forgery prevention that it is desirable.